libpayload: New CBFS to support multiple firmware media sources.

Upgrade CBFS in libpayload to use new media-based implementation from coreboot
( http://review.coreboot.org/#/c/2182/ ).

Old CBFS functions (cbfs_find, cbfs_find_file, get_cbfs_header) are still
supported, although the recommended way is to use new CBFS API.

To migrate your existing x86 payload source:
	- Change cbfs_find to cbfs_get_file
	- Change cbfs_find_file to cbfs_get_file_content
	- Prefix every CBFS call with a CBFS_DEFAULT_MEDIA argument.

Ex, char *jpeg_data = cbfs_find_file("splash.jpg", CBFS_TYPE_BOOTSPLASH);
 => char *jpeg_data = cbfs_get_file_content(
		CBFS_DEFAULT_MEDIA, "splash.jpg", CBFS_TYPE_BOOTSPLASH);

The legacy setup_cbfs_from_{ram,flash} is also supported, although the better
equivalent is to make a new media instance:
	struct cbfs_media ram_media;
	init_cbfs_ram_media(&ram_media, start, size);
	char *data = cbfs_get_file_content(&ram_media, "myfile", my_type);

Verified by being successfully linked with filo.

Change-Id: If797bc7e3ba975d7e3be905c59424f7a93b8ce11
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: http://review.coreboot.org/2191
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Anton Kochkov <anton.kochkov@gmail.com>

payloads/libpayload/include/stdint.h

@@ -32,4 +32,5 @@
 #include <arch/types.h>
 
 typedef unsigned long uintptr_t;
+typedef long intptr_t;
 #endif